A known in-vehicle device is configured to realize hands-free conversations and voice recognition processes, while a microphone is installed in a dashboard, a ceiling, or a steering wheel of a vehicle. For devices of this type that are configured to collect sound (hereinafter, “sound collecting devices”), it has been proposed, for the purpose of enhancing the capabilities thereof, to provide the devices with a microphone array structured by arranging a plurality of microphones and to control the directionality of the microphone array by exercising beam forming control (see Patent Literature 1, for example).
Patent Literature 1 describes providing a position detector configured to detect the position of the head of a speaking person present in an automobile on the basis of the position of a rear-view mirror or a seat provided for the automobile, so that a directionality arithmetic process is performed on the basis of the detected position of the head and positions of microphones.